3-(2-Acylaminophenyl)-1,2,4-triazines

ABSTRACT

3-(2-Acylaminophenyl)-1,2,4-triazine compounds such as 3-(2(3,4-dichlorobenzoyl)aminophenyl)-1,4,5,6-tetrahydro-1-ethyl1,2,4 -triazine are prepared by the reaction of a 3-(2aminophenyl)-4-loweralkyl-1,4,5,6-tetrahydro-1,2,4-triazine with an acid chloride. The compounds are intermediates for preparing triazinoquinazolines having pharmacological activity.

United States Patent Trepanier et al.

3-( Z-ACYLAMINOPHENYL l ,2,4- TRIAZINES Inventors: Donald L. Trepanier; Shyam Sunder, both of Midland. Mich Assignee: The Dow Chemical Company,

Midland. Mich.

Filed: Nov. 4, l974 App! No: 520,575

US. Cl r r r r d 260/248 AS; 424/249 Int. Cl. v. C07D 253/06 Field of Search 260/248 AS Nov. I1, 1975 Primary E.umriner-John MY Ford Attorney, Agent, or Firm-Maynard R Johnson {57] ABSTRACT 34 Z-Acyluminophenyhl .2.4-triuzine compounds such as 3[2-(lidichiorobenzoyl)aminophenylL l.4.5,6-tctruhydroi ethyll .ZAKfllZlllQ are prepared by the reaction of a 3-(Z-uminophenyl)-4-lowcrulkyli, lfi -tetruhydrd1,2.4-triuzine with an acid chloride The compounds are intermediates for preparing triazinoquinuzolines halving pharmacological activity.

4 Claims. N0 Drawings 3-( Z-ACYLAMINOPHENYL l ,2,4-TRIAZINES SUMMARY OF THE INVENTION N l N In the above formula, and elsewhere in the present specification, R represents phenyl or substitutedphenyl having one, two or three substituents selected from halo, cyano, and lower alkyl or loweralkoxy of one to three carbon atoms, and R represents loweralkyl of one to three carbon atoms. The compounds are crystalline solids, generally having melting points between about l20 and 200C, The term halo as herein employed refers to fluoro, chloro and bromo.

The triazinoquinazoline compounds prepared front the compounds of the invention arecrystalline solids at ordinary temperatures. The triazinoquinazoline compounds have phannacological activity, and can be administered to animals in the study of chemical effects on the central nervous system and respiratory tract. In

particular the compounds can be used as anti-depressants, barbiturate potentiators, analgesics, or histamine antagonists, as indicated by their activity in standard phannacological evaluation procedures. The type and degree of pharmacological activity typically varies some according to such factors as specific compound employed, dosage rate, dosage route, and size, age and macological use the compounds wherein R is phenyl or mono-substituted phenyl are particularly preferred.

PREPARATION AND USE OF THE COMPOUNDS The compounds of the invention are prepared by the reaction of 3-(2-aminophenyl)-l-methyl-l,4,5,6-tetrahydro-1,2,4-triazine (Formula ll) with an acid chloride of Formula Ill to obtain the corresponding 3-( 2- acylaminophenyl )-l ,4,5 ,-tetrahydro- 1 -methyl- 1 ,2,4- triazine intermediate of Formula I. They are used in a thermal cyclodehydration process to obtain a o-substituted-3 ,4-dihydro-2-methyL2H- l ,2,4-triazino[ 4,3- clquinazoline of Formula IV.

species of animal and effect to be produced. For pharrm N H u l200C.

(III) nil-c1 In the above formulae R has the significance set out above with respect to Formula I.

The reaction of the aminophenyltriazine and the acid chloride proceeds when the reactants are contacted and mixed, in the presence of an inert organic solvent as a reaction medium and a trialkylamine as a hydrogen halide acceptor. Suitable inert solvents include halogenated hydrocarbons and methylene chloride is a preferred solvent. The reaction proceeds at temperatures from about 25 to the boiling temperature of the mixture. It is generally desirable to heat the reaction mixture tothe boiling temperature under reflux. The reaction is generally complete within about 2 to about 12 hours, depending upon temperature and choice of solvent and acid chloride. The acylaminophenyl triazine product can be separated by conventional procedures, such as evaporation of reaction medium or cooling of the reaction mixture to induce crystallization of the compound, followed by filtration. The product can be purified by conventional procedures such as recrystallization and washing.

The exact proportions of the reactants to be employed are not critical, some of the desired product being obtained when the reactants are combined over a wide range of proportions. The reaction consumes the reactants in equimolar proportions and in a preferred procedure, the reactants are employed in proportions fromsubstantially equimolar amounts of each reactant to about 10 percent molar excess of either reactant.

The cyclodehydration of the 3-( 2-acylaminophenyl)- l-methyll ,4,5 ,-tetrahydrol ,2,4-triazine is carried out by heating the triazine compound at a temperature of from about l70200C. The reaction is preferably carried out without use of a solvent, and is generally complete in from about 0.5 to about 2 hours. The product can be purified by conventional procedures, such as recrystallization.

in lieu of the above thermal cyclodehydration of the 3-( 2-acylaminophenyl )-l -methyl- 1 ,4,5,6-tetrahydro- 1,2,4-triazines, compounds of the invention can also be used in a polyphosphoric acid catalyzed cyclodehydration process. The reaction proceeds when the acylaminophenyl triazine and sufficient polyphosphoric acid are contacted and mixed. Generally, a l0 to 20 fold excess by weight of polyphosphoric acid is preferred. The reaction proceeds at temperatures from about C. to about 125C. or higher, and is generally complete in from about 0.5 to about 3 hours. The triazino[4,3-c]quinaz0line product is obtained as a mixture with the corresponding 3,4-dihydro-4-1oweralkyl-6-substituted-2l-l-1,2,4-triazino[2,3-c1quinazoline isomer, corresponding to the formula:

The relative amounts of the isomers can be changed by increasing reaction temperature to increase the concentration of the triazino[4,3-c]quinazo1ine isomer (formula IV) in the product. The isomers can be separated by conventional procedures such as chromatography on silica gel with an ethyl acetate eluant, and separately purified by conventional procedures.

DESCRIPTION OF PREFERRED EMBODIMENTS The following examples illustrate the invention but are not to be construed as limiting the same.

EXAMPLE 1 The 3-(2-acylaminophenyl)-1,4,5,6-tetrahydro- 1,2,4-triazines listed in Table 1 below are prepared as follows: 0.1 mole 3-(2-aminopheny1)-1-methy1-1,4,5,6- tetrahydrol ,2,4-triazine is mixed with milliliters triethylamine and 300 milliliters of methylene chloride while a solution of 0.1 mole of the corresponding acid chloride of formula III in a minimal amount of methylene chloride is added dropwise with stirring. When the addition is complete, the reaction mixture is heated, with stirring, at the boiling temperature under reflux for about 6 hours. The mixture is cooled, washed with water, dried over anhydrous magnesium sulfate, and evaporated under reduced pressure to obtain the triazine intermediate. Yields are between 67 and 91 percent of theoretical.

Similarly, 3-[ 2-( 3 ,4,S-trichlorobenzoylamino phenyl]- l -ethy1- 1 ,4,5,6-tetrahydro-1 ,2,4-triazine, having a molecular weight of 412; and 3-[2-(4-isopropylbenzoy1amino)pheny1]- 1 -n-propyl-1 ,4 ,5 ,G-tetrahydro- 1,2,4-triazine, having a molecular weight of 364, are prepared.

EXAMPLE 2 3-(2-Benzoylaminopheny1)-1-methy1-1,4,5 ,6-tetrahydro-1,2,4-triazine (5.0 grams) is stirred in grams polyphosphoric acid at C. for 1 hour. The mixture is cooled, diluted with ice and water, made a1- kaline by addition of sodium carbonate, and extracted with chloroform. The chloroform extract is washed with water, dried over anhydrous magnesium sulfate and evaporated under reduced pressure. The residue is passed through a column of 500 grams silica gel 60-200 mesh using ethyl acetate as an eluant. The first product recovered is 3,4-dihydro-2-methy1-6-pheny1-2H-1,2,4- triazino[4,3-c]quinazoline, a yellow crystalline solid melting at l42-144C. The second product is the white crystalline solid 3,4-dihydro-4-methyl-6-phenyl- 2H- 1 ,2,4-triazino[ 2,3-c lquinazoline, melting at 206-207C. Structure is confirmed by proton magnetic resonance and elemental analysis. The weight ratio of the first named product to the second named product is about 40:60.

The reaction is carried out again at 25C. instead of 100C. and the product ratio obtained is 60 parts of the first product to 40 parts of the second. The triazino[2,3-c]quinazoline isomers of the triazino[4,3- b]quinazolines listed in Table 11, Example 3, are prepared in substantially the same procedure.

EXAMPLE 3 The compounds listed below in Table II are prepared by heating about 10 grams of the corresponding 3-(2- acylaminophenyl 1 -methyl- 1 ,4,5 ,6-tetrahydro- 1 ,2,4- triazine prepared as set out in Example 1 in an oil bath at l80-200C. for one hour without solvent. After cooling to room temperature, the residue is purified by recrystallization. The compounds correspond to Formula 1V wherein R' is methyl.

TABLE 1 R Melting Point.C Elemental Analysis Calcd. Found C H N C H N CJ-l -126 69.36 6.16 19.03 69.31 6.38 18.73

3.4-C1 C H, 162-163 56.20 4.44 15.42 56.04 4.63 15.21

3-BIC.H., 167-168 54.69 4.59 15.01 54.57 4.71 15.00

4-BI.H4 166-167 54.69 4.59 15.01 54.50 4.62 14.91

4-O,NC H 219-221 60. 16 5.05 20.63 60.01 5.07 20.35

4-NCCJ-I 206-208 67.69 5.36 21.93 67.71 5.25 21.68

2-CH;C H, 118-119 70.10 6.53 18.16 70.35 6.51 18.41

Z-CIfiOCJL -152 66.64 6.21 17.27 66.91 6.22 16.96

3.4,5-(CH,O)C,H, 111-113 62.48 6.29 14.57 62.25 6.58 14.45

4-FC,H." 142-144 65.36 5.48 17.93 65.60 5.67 17.99

'Recrystallized from inopropanol. All others recrystallized from ethanol.

TABLE 11 R Melting Point.C Elemental Analysis Calcd. Found C H N C H N Z-FCJ'L 132-133 69.37 5.13 19.03 69.60 5.11 19.10 4-FC H 157-158 69.37 5.13 19.03 69.65 5.03 18.97 4-CH,C.H.* 134-135 74.45 6.24 19.29 74.55 6.38 19.42 4-NCCJ-l, 189-190 71.73 5.01 23.24 71.46 4.99 22.98 3-BI'CJ'14 186-187 57.47 4.25 15.77 57.23 4.49 15.62 4-BIC H 183-184 57.47 4.25 15.77 57.41 4.51 15.81 3,4,5-(CH,O);,C,H, 186-187 65.55 6.05 15.29 65.59 6.19 15.01 3.4-Cl,C.,H= 184-185 59.14 4.08 16.23 59.19 4.21 16.08 C Hfl 142-143 73.88 5.83 20.27 73.62 5.73 19.99

Recrystallized from isopropanol. All others recrystallized from ethanol.

In standard pharmacological evaluation procedures, (See, e.g., US. Pat. Nos. 3,64l,019-3,485,92l) the compounds of Example 3 wherein R is 2-fluorophenyl, 3-bromophenyl or 4-fluorophenyl are found to block histamine induced contraction of isolated guinea pig trachea at a concentration of 120 milligrams per liter. The compounds of formula l wherein R is 2-fluorophenyl, 4-cyanophenyl, 4-bromophenyl, phenyl or hydro- 100-120C. to drive off hydrogen sulfide of reaction. Ethanol is added and the mixture is boiled for 30 minutes under reflux, cooled, diluted with ether until a precipitate forms, and filtered. The aminophenyl triazine filter cake is recrystallized from isopropanol and found to melt at l40l4lC.

What is claimed is:

l. A 3-(2-acylaminophenyl)-1,2,4-triazine corregen and are all phenyl, 4-bromophenyl, phenyl or hy- |0 sponding to the formula:

ample 4 wherein R is hydrogen or 4-methylphenyl exhibit analgesic activity in inhibiting characteristic writhing induced in mice by intraperitoneal injection of aqueous hydrochloric acid.

The 2-aminophenyl triazine starting material can be prepared by reacting 2-aminophenyl cyanide with hydrogen sulfide in pyridine and triethylamine to obtain 2-aminophenylthiobenzamide, and then reacting the thiobenzamide with a l-loweralkyl-l-(2-aminoethyl)- hydrazine. For example, 100 grams of Z-aminophenyl cyanide in a mixture of 500-600 milliliters of pyridine and 100 milliliters triethylamine is stirred at about C. while hydrogen sulfide is passed through the mixture for three hours. The product is separated, and 4 grams of the product are mixed with 1.8-2.0 grams 1- methyl- 1-( 2-arninoethyl)hydrazine for 2 hours at about HN N 

1. A 3-(2-ACYLAMINOPHENYL)-1,2,4-TRIAZINE CORRESPONDING TO THE FORMULA:
 2. A compound of claim 1 wherein R represents phenyl or mono-substituted phenyl.
 3. A compound of claim 1 wherein R'' is methyl.
 4. A compound of claim 3 wherein R is phenyl. 